docs: Add LCG generator to example

apps/typegpu-docs/src/examples/algorithms/probability/constants.ts

@@ -1,10 +1,12 @@
-import { Distribution } from './types.ts';
+import { Distribution, Generator } from './types.ts';
 
 export const popupCooldown = 100000;
 export const cameraPositionGeo = [0, 0, 0.5];
 export const cameraPositionHist = [0, 0, 0.2];
 export const initialCameraAngle = 15;
 export const numSamplesOptions = [100, 1000, 2000, 5000, 10000, 50000];
 export const initialNumSamples = numSamplesOptions[2];
+export const initialGenerator: Generator = Generator.BPETER;
+export const generators: Generator[] = Object.values(Generator);
 export const initialDistribution: Distribution = Distribution.NORMAL;
 export const distributions: Distribution[] = Object.values(Distribution);

apps/typegpu-docs/src/examples/algorithms/probability/executor.ts

@@ -11,7 +11,11 @@ import type {
   TgpuSlot,
 } from 'typegpu';
 import * as d from 'typegpu/data';
-import { randf } from '@typegpu/noise';
+import {
+  randf,
+  randomGeneratorSlot,
+  type StatefulGenerator,
+} from '@typegpu/noise';
 
 export class Executor {
   // don't exceed max workgroup grid X dimension size
@@ -36,7 +40,10 @@ export class Executor {
       & StorageFlag,
     ]
   >;
-  readonly #pipelineCache: Map<TgpuFn, TgpuComputePipeline>;
+  readonly #pipelineCache: WeakMap<
+    TgpuFn,
+    WeakMap<StatefulGenerator, TgpuComputePipeline>
+  >;
 
   constructor(root: TgpuRoot) {
     this.#root = root;
@@ -93,34 +100,54 @@ export class Executor {
     });
   }
 
-  cachedPipeline(distribution: TgpuFn<() => d.Vec3f>) {
-    if (!import.meta.env.DEV) {
-      throw new Error('Function only for testing purposes');
+  #pipelineCacheHas(
+    distribution: TgpuFn<() => d.Vec3f>,
+    generator: StatefulGenerator,
+  ): boolean {
+    const generatorMap = this.#pipelineCache.get(distribution);
+    if (!generatorMap) {
+      return false;
     }
 
+    return generatorMap.has(generator);
+  }
+
+  #pipelineCacheSet(
+    distribution: TgpuFn<() => d.Vec3f>,
+    generator: StatefulGenerator,
+    pipeline: TgpuComputePipeline,
+  ) {
     if (!this.#pipelineCache.has(distribution)) {
+      this.#pipelineCache.set(distribution, new Map([[generator, pipeline]]));
+      return;
+    }
+
+    // biome-ignore lint/style/noNonNullAssertion: just checked it above
+    this.#pipelineCache.get(distribution)!.set(generator, pipeline);
+  }
+
+  pipelineCacheGet(
+    distribution: TgpuFn<() => d.Vec3f>,
+    generator: StatefulGenerator,
+  ): TgpuComputePipeline {
+    if (!this.#pipelineCacheHas(distribution, generator)) {
       const pipeline = this.#root['~unstable']
+        .with(randomGeneratorSlot, generator)
         .with(this.#distributionSlot, distribution)
-        .withCompute(this.#dataMoreWorkersFunc)
+        .withCompute(this.#dataMoreWorkersFunc as TgpuComputeFn)
         .createPipeline();
-      this.#pipelineCache.set(distribution, pipeline);
+      this.#pipelineCacheSet(distribution, generator, pipeline);
     }
 
     // biome-ignore lint/style/noNonNullAssertion: just checked it above
-    return this.#pipelineCache.get(distribution)!;
+    return this.#pipelineCache.get(distribution)!.get(generator)!;
   }
 
   async executeMoreWorkers(
     distribution: TgpuFn<() => d.Vec3f>,
+    generator: StatefulGenerator,
   ): Promise<d.v3f[]> {
-    let pipeline = this.#pipelineCache.get(distribution);
-    if (!pipeline) {
-      pipeline = this.#root['~unstable']
-        .with(this.#distributionSlot, distribution)
-        .withCompute(this.#dataMoreWorkersFunc as TgpuComputeFn)
-        .createPipeline();
-      this.#pipelineCache.set(distribution, pipeline);
-    }
+    const pipeline = this.pipelineCacheGet(distribution, generator);
 
     pipeline
       .with(this.#bindGroupLayout, this.#bindGroup)

apps/typegpu-docs/src/examples/algorithms/probability/helpers.ts

@@ -1,8 +1,8 @@
 import tgpu from 'typegpu';
-import { randf } from '@typegpu/noise';
+import { BPETER, LCG, randf, type StatefulGenerator } from '@typegpu/noise';
 import * as d from 'typegpu/data';
 
-import { Distribution, PlotType, type PRNG } from './types.ts';
+import { Distribution, Generator, PlotType, type PRNG } from './types.ts';
 import * as c from './constants.ts';
 
 const normal = d.vec3f(1.41, 1.41, 0);
@@ -96,3 +96,11 @@ const distributionCameras = {
 export function getCameraPosition(distribution: Distribution): number[] {
   return distributionCameras[distribution];
 }
+
+const GENERATOR_MAP = {
+  [Generator.BPETER]: BPETER,
+  [Generator.LCG]: LCG,
+};
+
+export const getGenerator = (gen: Generator): StatefulGenerator =>
+  GENERATOR_MAP[gen];

apps/typegpu-docs/src/examples/algorithms/probability/index.ts

@@ -2,25 +2,28 @@ import tgpu from 'typegpu';
 
 import { Plotter } from './plotter.ts';
 import { Executor } from './executor.ts';
-import type { Distribution } from './types.ts';
+import type { Distribution, Generator } from './types.ts';
 import * as c from './constants.ts';
-import { getCameraPosition, getPRNG } from './helpers.ts';
+import { getCameraPosition, getGenerator, getPRNG } from './helpers.ts';
 
 const root = await tgpu.init();
 
 const executor = new Executor(root);
 const plotter = new Plotter();
 
 let currentDistribution = c.initialDistribution;
+let currentGenerator = c.initialGenerator;
 
 const replot = async (
   currentDistribution: Distribution,
+  currentGenerator: Generator,
   animate = false,
 ) => {
   let samples = undefined;
   const prng = getPRNG(currentDistribution);
+  const gen = getGenerator(currentGenerator);
 
-  samples = await executor.executeMoreWorkers(prng.prng);
+  samples = await executor.executeMoreWorkers(prng.prng, gen);
   await plotter.plot(samples, prng, animate);
 };
 
@@ -63,7 +66,27 @@ export const controls = {
   'Reseed': {
     async onButtonClick() {
       executor.reseed();
-      await replot(currentDistribution, true);
+      await replot(
+        currentDistribution,
+        currentGenerator,
+        true,
+      );
+      plotter.resetView(getCameraPosition(currentDistribution));
+    },
+  },
+  'Generator': {
+    initial: c.initialGenerator,
+    options: c.generators,
+    onSelectChange: async (value: Generator) => {
+      if (currentGenerator === value) {
+        return;
+      }
+      currentGenerator = value;
+      await replot(
+        currentDistribution,
+        currentGenerator,
+        true,
+      );
       plotter.resetView(getCameraPosition(currentDistribution));
     },
   },
@@ -78,6 +101,7 @@ export const controls = {
       currentDistribution = value;
       await replot(
         currentDistribution,
+        currentGenerator,
         true,
       );
       plotter.resetView(getCameraPosition(currentDistribution));
@@ -90,20 +114,25 @@ export const controls = {
       executor.count = value;
       await replot(
         currentDistribution,
+        currentGenerator,
       );
     },
   },
   'Test Resolution': import.meta.env.DEV && {
     onButtonClick() {
-      c.distributions
-        .map((dist) =>
-          tgpu.resolve({
+      for (const dist of c.distributions) {
+        for (const gen of c.generators) {
+          const code = tgpu.resolve({
             externals: {
-              f: executor.cachedPipeline(getPRNG(dist).prng),
+              p: executor.pipelineCacheGet(
+                getPRNG(dist).prng,
+                getGenerator(gen),
+              ),
             },
-          })
-        )
-        .map((r) => root.device.createShaderModule({ code: r }));
+          });
+          root.device.createShaderModule({ code });
+        }
+      }
     },
   },
 };

apps/typegpu-docs/src/examples/algorithms/probability/types.ts

@@ -69,3 +69,10 @@ export interface SimplePRNG {
   plotType: PlotType;
   prng: TgpuFn<() => d.Vec3f>;
 }
+
+export const Generator = {
+  BPETER: 'bpeter (default)',
+  LCG: 'lcg',
+} as const;
+
+export type Generator = typeof Generator[keyof typeof Generator];

apps/typegpu-docs/src/examples/tests/uniformity/prngs.ts

@@ -1,6 +1,4 @@
-import { BPETER, type StatefulGenerator } from '@typegpu/noise';
-
-import { LCG } from './lcg.ts';
+import { BPETER, LCG, type StatefulGenerator } from '@typegpu/noise';
 
 export const PRNG = {
   BPETER: 'bpeter (default)',

packages/typegpu-noise/src/generator.ts

@@ -1,6 +1,6 @@
 import tgpu, { type TgpuFn, type TgpuFnShell, type TgpuSlot } from 'typegpu';
 import * as d from 'typegpu/data';
-import { add, cos, dot, fract } from 'typegpu/std';
+import { add, cos, dot, fract, pow } from 'typegpu/std';
 
 export interface StatefulGenerator {
   seed: TgpuFn<(seed: d.F32) => d.Void> | ((seed: number) => void);
@@ -47,6 +47,50 @@ export const BPETER: StatefulGenerator = (() => {
   };
 })();
 
+/**
+ * Naive Linear Congruential Generator (LCG)
+ */
+export const LCG: StatefulGenerator = (() => {
+  const seed = tgpu.privateVar(d.u32);
+
+  const u32To01Float = tgpu.fn([d.u32], d.f32)`(val){
+    let exponent: u32 = 0x3f800000;
+    let mantissa: u32 = 0x007fffff & val;
+    var ufloat: u32 = (exponent | mantissa);
+    return bitcast<f32>(ufloat) - 1f;
+  }`;
+
+  return {
+    seed: (value: number) => {
+      'kernel';
+      seed.$ = d.u32(value * pow(32, 3));
+    },
+    seed2: (value: d.v2f) => {
+      'kernel';
+      seed.$ = d.u32(value.x * pow(32, 3) + value.y * pow(32, 2));
+    },
+    seed3: (value: d.v3f) => {
+      'kernel';
+      seed.$ = d.u32(
+        value.x * pow(32, 3) + value.y * pow(32, 2) +
+          value.z * pow(32, 1),
+      );
+    },
+    seed4: (value: d.v4f) => {
+      'kernel';
+      seed.$ = d.u32(
+        value.x * pow(32, 3) + value.y * pow(32, 2) +
+          value.z * pow(32, 1) + value.w * pow(32, 0),
+      );
+    },
+    sample: () => {
+      'kernel';
+      seed.$ = seed.$ * 1664525 + 1013904223; // % 2 ^ 32
+      return u32To01Float(seed.$);
+    },
+  };
+})();
+
 // The default (Can change between releases to improve uniformity).
 export const DefaultGenerator: StatefulGenerator = BPETER;
 

packages/typegpu-noise/src/index.ts

@@ -145,6 +145,7 @@ export {
   BPETER,
   // The default (Can change between releases to improve uniformity).
   DefaultGenerator,
+  LCG,
   // ---
   randomGeneratorShell,
   randomGeneratorSlot,